Methine dyes for synthetic fibers



densationreaction with the aldehyde. the cyanoethyl cyanoacetate group in the dye molecule is in the N alkylside United States Patent O i 2,789,125 METHINE'DYES FOR SYNTHETIC FIBERS "Nicholas J. Karlinos, Chicagm'IlL; James-B.'Normiugton,

Belvidere,'N. J., and William W. Williams, Easton, Pa., assignors to General Anilinexga'l iim'{,orporatien, New York, N. Y., a corporationof Delaware No Drawing. ApplicationDecniberiSjI9S3, Serial No. 398,408

3 Claims. (Cl. 260465) .This invention relates-to a hewclass of methinedyes which not only dye synthetic fibers with excellent wash, light, and chlorine fastnessgbut are also brilliant in color and possess fluorescent properties.

We have found that methine dyes obtained by condensing a 2-substituted-4-dialkyl(or diialkylcarboxyalkyll)amino benzaldehyde with-an alkyl cyanoacetate or cyanoethyl'cyanoacetate-in the presence of a basic or acid condensing agent yield dyes which are not only of high tinctorial '-strength and' 'of excellent lightfichlorine and wash fastness, and good sublimation properties, but

' also-becauseof-their brilliance'and/or fluorescence are adaptable as fluorescent pigments and asbrightening agents. The 'methineidyes are particularly adaptable for dyei'ngthe currently available synthetic fibers, such as,

acetate rayons, etc., to 'which they impart fluorescentgreen-yellow shades ot excellentlight and wash fastn'ess and display exceptionally high tinctorial strength.

These 'methine dyes are characterized by the following general formula:

wherein R- represents a lower alkyl group, e. g.,"methyl,

ethyl, propyl, butyl, etc. or an alkylcarboxyalkyl group in which each 'of 'th'e alkyls is a lower'alkyl, and R1 represents either' a halogen *(e. g., chlorine; bromine,

iodine, or'fiuorine), hydroxy,-or a lower alkoxy, e. 'g.,

methoxy; ethoxy, propoxy, butoxy, etc.

'lniaddition todyeing acetate rayon in exceptionally bright yellow and green-yellow-shades possessiong outstanding-light, wash"ahdfchlorine fast'ness. the dyes of -the present invention exhibit a' marked'increase in tinctorial strength. On the average, an increase of 100% 'Inore or'less, "is obtain'ed -when employing cyanoethyl cyanoacetate in place of'alkyl .cyanoacetate in the'con- The presence of also contributes to their excellent light and wash fastness. The presence of either an ortho alkyl or the cyanoethyl ester grouping serves-to provide the methine dyes with distinctly superior sublimation fastness and especially in the dyes containing both a cyanoethyl ester group and a lower alkyl group in the ortho-position to the methine linkage. 7

The methine dyes of the present invention containing a nuclear halogen substituent in the ortho-position to the methihe linkage"are'decidedly"superior "in "ti'n'c'torial strength to compounds wherein the halogen substituent In view of this nuclear halogen substituent, the dye'sin addition to the increased tinctorial strengthexhibit excellent wash and light fastness. This maintenance ofexcellent 'fastn'ess properties is unique and unexpected. It iswell recognized that a dye with high tinctorial "strength usually exhibits poor iastness properties when compared to a dye with inferior 2,789,125 *iaientd Apr. '16,?1957 ice tinctorial strength. This is dueto 'the 'fact"that fewer molecules are necessary for the dye 'of high tinctorial strength to achieve a'desired' dyeing etfect, and 'as a result fewer molecules are present to resist thedeleterious effect of light and washing.

In the case of the dyes containing a hydroxyl and allcoxy group in the ortho position' to the methine linkage, the dyes'are not only very brilliant but are also '2-chloro-4-dibutylaminobenzaldehyde including the biomo, fiuoro a'nd iododerivatives thereof.

2-methoxy-4-dimethylaminobenzaldehyde 2 ethoxy-4-d imethylaminobenzaldehyde -2'propoxy-4-dimethylaininobenzaldehyde 2-butoXy-4-dirnethylaminobenzaldehyde 2-hydroxy-4-dimethylarninobenzaldehyde 2-hydroxy-4-diethylaminobenzaldehyde 2-hydroxy-4-dipropylaminobenzaldehyde 2-hydroxy-4-dibutylaminobenzaldehyde 2-chloro-4-di( ethylcarboxyethyl) aminobenzaldehyde and the aldehydes of copending application S. N. 372,400 filed August' l, 1953 (E-1060).

All of the foregoing aldehydes are readily prepared by reacting the appropriate ln-SllbStltlltBd dialkyl aniline with dimethyl'forinamide. Typical processes in the presence 'of phosphorus oxychloride are illustrated under the following working examples.

The various alkyl cyanoacetates which may be condensed with the aldehycles are the following: methyl-, ethyl-, isopropyl-, -butyl-, and isobutylcyanoaoetates.

The cyanoethyl cyanoacetate utilized in the condensation reaction with any one of the foregoing aldehydes is prepared according to the method described in Example III; hereof. V

The following examples will describe the preparation of some of the methine dyestufis characterized by the fore- -going chemical formulae. It is to be understood that they are merely illustrative and that the invention claimed herein is not to be regarded'as restricted thereto.

Example 1 /CN (02m) lN'-ofa= o I O 02 C 7H5 O 02H:

Ethyl a-cyano -"4 (-diethyla'mlno) -2-ethoxycinnamate The intermediate, Z-ethoxy 4 diethylaminobenzaldehyde, was prepared by combining in a reaction flask 96.5 grams of N,N'-diethyl-m-phenetidin'e and 73 'grams' 'of dimethyl formamide. The mixture was cooled to 10 C.

andthere was added dropwise during 45 minutes 92 ml.

of phosphorus 'oxychloride. After'the addition the reaction mixture was warmed on a steam'bath' for 4"hours, cooled and drowned in' ice water.

To precipitate the product from the strongly acid solution, there was added 300 ml. of 40% sodium hydroxide solution until the pH was between 35. The tan crystalline product that resulted was collected, washed and dried. There was obtained 42 grams of a material melting at 458 C., or 3.3% of the theoretical amount.

11.05 grams of the above aldehyde, 6.8 grams of ethyl cyanoacetate, 30 ml. of isopropanol and 5 drops of piperidine were added to a reaction flask and mixed. The

reaction mixture was heated under mild reflux for one hour. Upon cooling, the bright orange solid that separated was collected and dried. The solid is a brilliant red-orange and fluoresces strongly under u. v. The yield was 9 grams; melting point 74-5 C. (57% of theory).

7 Example 11 (CzHa) 2N O H: C\

l C 0202B: OH

Ethyl a-cyano-4 (dlethylamino) -2-hydroxycinnamate The intermediate, 2-hydroxy-4-diethylaminobenzaldehyde, was prepared by reacting about 132 grams of mdiethylaminoph'enol, 110 grams of dimethylformamide v and 138 ml. of phosphorus oxychloride in a manner similar to that outlined in the first paragraph of Example I.

There was obtained 44 grams of a tan solid, melting point 62 C.; 30% of the theoretical amount.

9.6 grams of the aldehyde and 6 grams of ethyl cyanoacetate were refluxed as in Example I. The yield obtained amounted to 7 grams or 49% of theory. The final product has a melting point of 1479 C.

Example III Cyanoethyl a-cyano-4 (diethylamino) -2-ethoxyclnnamate benzene was removed by distillation and the residue taken up in ethyl acetate. After washing with dilute sodium carbonate solution to remove the free acids present, the organic layer was dried over sodium sulfate, filtered and distilled. There was obtained about 41 grams of product boiling at 1504/0.7-0.8 mm.

Calcd. for CsHsOzNz; N, 20.3%. Found N, 20.1%.

Example IV Ethyl a-cyano 4( diethylamlno -2-methoxycinnamate COzCeHS The intermediate, 2-methoxy-4-diethylaminobenzaldehyde, was prepared in the following manner:

In a l-liter flask were placed about 100 grams (0.49 mole) of N,N-dieth yl-m-anisidine and 200 ml. benzene.

, anilide.

Keeping the temperature at 0-10 C. by means of an ice bath there was added simultaneously during 40 minutes: 153.5 grams (1 mole) of phosphorus oxychloride and 73 grams (1 mole) of N-methyl formanilide. A yellow solid was formed. The mixture was allowed to warm to room temperature (solid dissolved) and then heated under reflux for 5 hours and cooled over night. The mixture was drowned in ice-water, made alkaline-to Deltapaper by means of 400 ml. of 40% sodium hydroxide solution and the organic layer separated. After washing with water, the benzene layer was dried, the solvent removed, and the residue distilled under reduced pressure.

Into a reaction flask were placed 16.2 grams (0.085 mole) of 2-methoxy-4-diethylaminobenzaldehyde, 10.5 ml. of ethyl cyanoacetate, 30 ml. of isopropanol and 5 drops piperidine.

The reaction mixture was heated under reflux for one hour. Upon cooling, the solid that separated was collected and dried. The yield of product was 21.9. grams.

Example V oN (GrHshN CH=C\ Ethyl a-cyano-4 (diethylamino) -2-chloroclnnamate The intermediate, 2-chl0ro-4'(N,N-diethylamino)-benzaldehyde, was prepared in the following manner:

About 36.7 grams of N,N-diethyl-m-chloroaniline Were dissolved in ml. of benzene. While maintaining the temperature at 040 C. by means of an ice bath there was added dropwise during 1 hour a mixture of 37 ml. of phosphorus oxychloride and 50 ml. of N-rnethyl form- The reaction mixture was allowed to warm to room temperature and then warmed on a water bath at 50 C. for 2 hours. After cooling, the mixture was drowned in ice-water and the benzene layer separated. The organic layer was washed to remove any acid present, dried, the benzene removed and the residue distilled under reduced pressure. There was obtained 31 grams of product; boiling point 1325/0.6 mm. (73% of the theoretical amount).

Dimethyl formamide is advantageously employed instead of the N-methyl formanilide. Dimethyl formamide is commercially available at low cost, and results in a higher yield. Being completely water soluble it does not appear in the forerun as does N-methyl aniline derived from the N-methyl formanilide.

Into a reaction flask were placed 10.6 grams of 2- chloro-4-diethylaminobenzaldehyde, 6 ml. of ethyl cyanoacetate, 50 ml. of isopropanol and 5 drops of .piperidine. The reaction mixture was heated under reflux for one hour. Upon cooling, the solid that separated was collected and dried. The yield of the product was 12.5 grams about 81% of the theoretical amount. It has a melting point of 83.5 C.

Example VI (CSHB):NQCH=G 1 ooroinomou' Cyanoethyl a-eyano-2-chloro-4-dlethylaminoci1mamate Dye Color M. P

CN' Green-yellow 122-4 (oimo 0,o,H4 ,N--on=o AB: C 0 CaHtCN CN d0 104-8 (C2H5C ozca dzNgcH -c C O: C2H4 C N 0N .-do 64-5 (CzHrC O2CiHO1N-Q-C H=C Cl C 0205B;

The foregoing dyes, being essentially water-insoluble, are advantageously applied directly to the material undergoing coloration in the form of an aqueous dispersion or suspension, a satisfactory aqueous suspension is readily obtained by dissolving the dye in acetone and ethanol, adding a surface wetting agent and drawing the solution in hot water. More specifically, 10 to 100 milligrams of dye is dissolved in a mixture of 2 ml. of ethanol and 2 ml. of acetone, and 2 n11. of aqueous solution of sodium-N-methyl-N-oleoyl taurate and hot water is then added to bring the volume to 300 ml. A 10 gram sample of cellulose acetate or Dacron cloth is introduced and the dye bath gradually increased to 70-90 C. in the case of cellulose acetate or 70100 C. in the case of Dacron.

More permanent dispersions are obtained by grinding the dye to a paste in the presence of a sulfonated oil, soap, sodium lignin sulfonate, or other suitable dispersing agent. The paste may be used directly or dried, ground and stored for long periods without deterioration.

The textile material to be dyed or colored is ordinarily added to the dye bath at a lower temperature than that at which the main portion of the dyeing is to be conducted. For example, the fabric is introduced at a temperature of about 45-55 C., then the temperature is gradually raised to that selected for carrying out the dyeing operation. The temperature at which the dyeing is conducted may be varied depending upon the particular material undergoing coloration. It is understood by those skilled in the art, that the intensity of dyeing may be varied by varying the proportion of dye to material undergoing coloration. The amount of dye used can be, for example, /2% to 3% by weight of the textile material, although lesser or greater amounts of dye can be used.

As many apparently widely different embodiments of this invention may be made without departing from the spirit and scope thereof, it is to be understood that we do not wish to limit ourselves to the specific embodiments thereof except as defined by the following claims.

We claim: 1. Methine dyes for synthetic fibers having the following general formula:

(Ca lhN 3. A methine dye for synthetic fibers having the following formula:

(02 :N OH= C l C OICHsCHsON References Cited in the file of this patent UNITED STATES PATENTS Wahl Mar. 13, 1934 Taylor et a1. Ian. 29, 1952 OTHER REFERENCES Bauer et aL: Ber. Deut. Chem., vol. 63, pp. 2691-93 (1930). 

1. METHINE DYES FOR SYNTHETIC FIBERS HAVING THE FOLLOWING GENERAL FORMULA: 